Electronic control device

• US 8,306,688 B2
• Filed: 07/02/2009
• Issued: 11/06/2012
• Est. Priority Date: 07/04/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kura, Kaname, Nagata, Kouji
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): MOYER, DALE S
• Application Number:
  US12/496,758
• Publication Number:
  US 20100004814A1
• Time in Patent Office: 1,223 Days
• Field of Search: 701 291- 344, 701 99-115, 715/23, 715/25, 715 30- 31
• US Class Current: 701/33.2
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/2406 using essentially read only memories
• CPC Class Codes: F02D 41/2425 Particular ways of programming the data
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue

Abstract

An electronic control unit performs a process that stores into a buffer selected diagnostic trouble codes (DTC) currently in a volatile trouble code storage by selecting, from among multiple codes, a code that is to be saved in an EEPROM, when an ignition switch of a vehicle is turned off. Further, the DTC stored in the buffer is written in the EEPROM. If the electronic control unit receives, from a scan tool, a command that instructs erasure of the DTC in the volatile trouble code storage, the above-described process is performed before erasing the DTC from the volatile trouble code storage.

Claims

1. An electronic control device capable of performing processing indicated by a command when receiving the command from outside of the electronic control device, the device comprising:

a diagnosis unit for performing diagnosis of at least one diagnosis item while energized and for storing, to a trouble information storage, a diagnostic trouble code (DTC) indicative of a trouble detected by the diagnosis;

a non-volatile memory that is capable of storing data in a re-writable manner;

an information selection unit for selecting, from among DTCs in the trouble information storage, DTC to be saved in the non-volatile memory as a permanent diagnostic trouble code (PDTC) based on a save criterion and storing the DTC selected in a buffer as a PDTC; and

a trouble information preservation unit for performing preservation of the DTC by writing the PDTC stored in the buffer into the non-volatile memory after a turning-off of an ignition switch of a vehicle or upon receiving a command from outside of the device, wherein

the trouble information preservation unit causes the information selection unit to select the DTC prior to performing processing indicated by the received command whenever the received command is a specific command that indicates erasure of the DTC from the trouble information storage.

2. The electronic control device of claim 1, wherein

the buffer is a memory that is backed up by a supply of a back-up power.

3. The electronic control device of claim 1, wherein,

when the specific command is received, the information selection is operated and the PDTC in the buffer is written in the non-volatile memory.

4. The electronic control device of claim 2, wherein,

when the specific command is received, an integrity of a back-up power supply unit for supplying the back-up power for the buffer is determined, and

when the back-up power supply unit is not determined as integral, the information selection unit is operated and the PDTC in the buffer is written in the non-volatile memory.

5. An electronic control device capable of performing processing indicated by a command when receiving the command from outside of the electronic control device, the device comprising:

a diagnosis unit for performing diagnosis of at least one diagnosis item while energized and for storing, to a trouble information storage, a diagnostic trouble code (DTC) indicative of a trouble detected by the diagnosis;

a non-volatile memory that is capable of storing data in a re-writable manner; and

an information selection unit for selecting, from among DTCs in the trouble information storage, DTC that fulfills a save criterion for storing the information in the non-volatile memory and writing the DTC selected in the non-volatile memory, as a permanent diagnostic trouble code (PDTC), wherein,

when a specific command for instructing erasure of the DTC in the trouble information storage is received from outside of the device, at least the DTC fulfilling the save criterion is recorded in a record unit as a DTC, contents of which is not erased by the processing indicated by the specific command, before performing the processing indicated by the specific command.

6. The electronic control device of claim 5, wherein

the record unit is a memory that has a supply of a back-up power.

7. The electronic control device of claim 5, wherein

the record unit is the non-volatile memory, and

when the specific command is received, the DTC fulfilling the save criterion in the trouble information storage is stored in the non-volatile memory as a PDTC, before performing the processing indicated by the specific command.

8. The electronic control device of claim 6, wherein

when the specific command is received, an integrity of the back-up power supply unit for supplying the back-up power for the record unit is determined,

when the back-up power supply unit is determined as integral, the DTC at least fulfilling the save criterion in the trouble information storage is written in the record unit as a PDTC from among the DTC, in the trouble information storage, and

when the back-up power supply unit is not determined as integral, the DTC fulfilling the save criterion in the trouble information storage is written in the record unit as a PDTC from among the DTC in the trouble information storage.

9. An electronic control device capable of performing processing indicated by a command when receiving the command from outside of the electronic control device, the device comprising:

a diagnosis unit for performing diagnosis of at least one diagnosis item while energized and for storing, to a trouble information storage, a diagnostic trouble code (DTC) indicative of a trouble detected by the diagnosis;

a non-volatile memory that is capable of storing data in a re-writable manner; and

an information selection unit for selecting, from among DTCs in the trouble information storage, at least one entry of DTC to be saved in the non-volatile memory as a permanent diagnostic trouble code (PDTC), wherein,

when a specific command for performing processing that instructs erasure of the DTC in the trouble information storage is received from outside of the device, the processing indicated by the specific command is performed after the information selection unit is operated.

10. The electronic control device of claim 9, wherein the specific command is a reset request command for the electronic control device.